The present invention relates to a propulsion control system for a motor vehicle having a propulsion system which includes an internal combustion engine with a shaft that can be coupled to a transmission system which includes a gearbox.
More specifically, the invention relates to a control system including                a control accelerator having associated electrical detector means,        sensor means operable to supply electrical signals indicative of the speed of rotation of the engine shaft and/or the speed at which the vehicle is moving, and        electronic control means operable to control the propulsion system of the motor vehicle in a predetermined manner in dependence on the signals supplied by the aforesaid detection means and the said sensor means.        
In a prior art method which is widely used, the command given by means of the accelerator pedal of a motor vehicle is interpreted by an engine management unit according to a so-called “driveability map” stored in a memory, which ensures that each position of the accelerator pedal and each speed of rotation of the drive shaft corresponds unequivocally to a pre-established drive torque value generated by the engine itself. In such a system, the command given by means of the accelerator is thus directly “translated” by the operating system of the engine into a value of drive torque transmitted to the drive shaft, in dependence on the speed of rotation of the engine.
According to a more recent method, described for example in the international Patent Application WO-A-01/02210, a system for controlling the propulsion of a motor vehicle includes control means operable, in a pre-established manner, to determine the power to be applied to the drive wheels in dependence on the detected position of the accelerator pedal and of the speed of the vehicle (either calculated or acquired), and then to calculate—in dependence on the value of power to be applied to the drive wheels and the speed of the vehicle—the drive torque which must be correspondingly generated by the engine. Such a system is essentially based on the idea of using the accelerator pedal not to control the drive torque generated by the engine but rather directly to control the power applied to the drive wheels of the motor vehicle. In such a system the accelerator pedal is of course of an entirely “passive” type.